Fluorescence microscopy is an essential technique for the study of biochemical processes in living cells. A major challenge in chemical research is the development of probes that selectively target specific biomolecules, cell structures, and organelles. In 2014 we described the fluorescent dye MitoBlue1, a nontoxic and particularly photoresistant fluorescent dye that specifically labels functional mitochondria with blue emission. Since current mitotracker dyes emit in the red and green region of the spectrum, MitoBlue provides a new detection wavelength, and significantly expands the possibilities of multiwavelength analysis of cellular processes. In collaboration with Prof. José Martínez-Costas, we continued the biochemical characterization of MitoBlue, and in 2020 we showed that MitoBlue is not just an static mitochondrial marker, but can be used to easily monitor the changes in mitochondrial quality control mechanisms in different cells and cellular conditions. After initial mitochondrial targeting, MitoBlue is progressively transported to lysosomes in various cell types and at different vital status. Transfer of MitoBlue from mitochondria to lysosomes is accelerated under oxidative stress and in aged cells, where mitochondrial quality control may be activated. Therefore, MitoBlue can be used to easily monitor the changes in mitochondrial quality control mechanisms in different cells and cellular conditions. MitoBlue staining pattern is unique among mitochondrial stains and recombinant fluorescent probes, allowing to monitor in a non-invasive dynamic fashion the mitochondrial recycling mechanism in a variety of situations in living cells. MitoBlue represents a unique tool for the study of these processes that will allow the detailed characterization of communication between mitochondria and lysosomes.
a) M. I. Sánchez, Y. Vida, E. Pérez-Inestrosa, J. L. Mascareñas, M. E. Vázquez, A. Sugiura, J. Martínez-Costas, Sci. Rep. 2020, 10, 3528; b) M. I. Sánchez, J. Martínez-Costas, J. L. Mascareñas, M. E. Vázquez, ACS Chem. Biol. 2014, 9, 2742–2747.